1. Field of the Invention
The present invention is related to a device for instant, automatic, pressurized percolation of food liquids, and especially of hot beverages such as coffee.
The invention is intended to enable the preparation, under entirely automated conditions and without human intervention except for sending an initial command signal, of a hot beverage such as an "espresso" type of coffee, i.e., delivered and made available to the consumer immediately upon exiting the percolation phase.
2. Discussion of Background Information
Devices disclosed up until now, and especially the device described in FR 86 02636 by the same inventor, are most often based on the use of a vertical cylinder constituting the infusion chamber into which is poured a certain quantity of ground coffee retained by a mesh constituting the base of the cylinder. A vertically displacing piston compresses the coffee powder, through which hot water is injected and then removed. The hot water generally gets into the cylinder by passing through the mobile compression piston, thereby necessitating flexible tubing which is generally fragile. The base of the cylinder is mobile and can rise within the latter so as to enable the extraction of the powder which is removed by means of a mobile scraper. The assembly is activated by means of generally complex and expensive mechanisms, comprising mechanical or other latching systems, and are controlled by electro-mechanical or electronic devices, attached to a series of micro-contacts, that often break down. The presence of the mobile piston above the cylinder renders the pouring action of the coffee powder therein clumsy, by requiring a complicated progression and mobile guide means. Finally, the hot water supply and removal of the infused coffee is done by a network of conduits that lead to loss of heat.
FR 90 00 820 and PCT/FR91/00030, by the same inventor, partially resolve these faults. They describe a device equipped with a mechanical group arranged horizontally in which the movements of the mobile elements are all caused by two racks with inverted horizontal displacements driving a series of cross-pieces sliding along columns, the infusion chamber with the horizontal axis, through which the hot water passes vertically, being extended by a horizontal, mobile filling chamber directly receiving the poured coffee powder, which is later removed by a scraper, also having a horizontal movement and moved by a rotational lever. A heater located immediately below the mechanical group is directly connected to the infusion chamber by quick connectors for the injection of water and removal of the infused coffee, without tubing, the infused coffee recrossing the body of the heater. The infusion chamber has a mobile base with a magnetic latching driving system. Finally, the mechanical group is driven by virtue of a quick coupling by a motor whose stoppage and reverse motion are directly controlled by an electronic torque sensor that controls the pressure and suppresses the microcontacts.
The machining of this device, however, is relatively complex and expensive, especially insofar as the cross-pieces, columns and scraper are concerned. In addition, magnetic latching is not completely reliable due to the risk of the accumulation of coffee powder on the magnetized elements.
The device as per the present invention, that brings a series of improvements to the devices of FR 90 00 820 and PCT/FR91/00030, overcomes all these disadvantages. In fact, it enables an automatic, pressurized percolation machine to be obtained that comprises a small number of elements that are extremely reliable, especially easy to maintain, having excellent heat yield and a competitive manufacturing price.